diff --git a/irc/channel.go b/irc/channel.go
index 06b73274..aff1bccf 100644
--- a/irc/channel.go
+++ b/irc/channel.go
@@ -17,20 +17,6 @@ type Channel struct {
 	topic     string
 }
 
-type ChannelSet map[*Channel]bool
-
-func (channels ChannelSet) First() *Channel {
-	for channel := range channels {
-		return channel
-	}
-	return nil
-}
-
-type ChannelCommand interface {
-	Command
-	HandleChannel(channel *Channel)
-}
-
 func IsChannel(target string) bool {
 	if target == "" {
 		return false
@@ -132,8 +118,8 @@ func (channel *Channel) ModeString() string {
 }
 
 func (channel *Channel) Join(client *Client) {
-	channel.members[client] = true
-	client.channels[channel] = true
+	channel.members.Add(client)
+	client.channels.Add(channel)
 	reply := RplJoin(client, channel)
 	client.replies <- reply
 	channel.replies <- reply
@@ -141,10 +127,6 @@ func (channel *Channel) Join(client *Client) {
 	channel.GetUsers(client)
 }
 
-func (channel *Channel) HasMember(client *Client) bool {
-	return channel.members[client]
-}
-
 //
 // commands
 //
@@ -162,7 +144,7 @@ func (m *JoinCommand) HandleChannel(channel *Channel) {
 func (m *PartCommand) HandleChannel(channel *Channel) {
 	client := m.Client()
 
-	if !channel.HasMember(client) {
+	if !channel.members.Has(client) {
 		client.replies <- ErrNotOnChannel(channel)
 		return
 	}
@@ -171,19 +153,19 @@ func (m *PartCommand) HandleChannel(channel *Channel) {
 	client.replies <- reply
 	channel.replies <- reply
 
-	delete(channel.members, client)
-	delete(client.channels, channel)
+	channel.members.Remove(client)
+	client.channels.Remove(channel)
 
 	// TODO persistent channels
 	if channel.IsEmpty() {
-		channel.server.DeleteChannel(channel)
+		channel.server.channels.Remove(channel)
 	}
 }
 
 func (m *TopicCommand) HandleChannel(channel *Channel) {
 	client := m.Client()
 
-	if !channel.HasMember(client) {
+	if !channel.members.Has(client) {
 		client.replies <- ErrNotOnChannel(channel)
 		return
 	}
diff --git a/irc/client.go b/irc/client.go
index 29e1cddb..39f3dfd8 100644
--- a/irc/client.go
+++ b/irc/client.go
@@ -23,8 +23,6 @@ type Client struct {
 	username   string
 }
 
-type ClientSet map[*Client]bool
-
 func NewClient(server *Server, conn net.Conn) *Client {
 	read := StringReadChan(conn)
 	write := StringWriteChan(conn)
@@ -73,6 +71,7 @@ func (c *Client) writeConn(write chan<- string, replies <-chan Reply) {
 
 func (client *Client) Destroy() *Client {
 	client.conn.Close()
+	close(client.replies)
 	return client
 }
 
diff --git a/irc/constants.go b/irc/constants.go
index 8362997e..56c5eede 100644
--- a/irc/constants.go
+++ b/irc/constants.go
@@ -9,6 +9,7 @@ var (
 
 const (
 	VERSION = "ergonomadic-1"
+	CRLF    = "\r\n"
 
 	// numeric codes
 	RPL_WELCOME           = 1
@@ -173,7 +174,7 @@ const (
 	Anonymous     ChannelMode = 'a'
 	BanMask       ChannelMode = 'b' // arg
 	ExceptionMask ChannelMode = 'e' // arg
-	InviteMask    ChannelMode = 'i' // arg
+	InviteMask    ChannelMode = 'I' // arg
 	InviteOnly    ChannelMode = 'i'
 	Key           ChannelMode = 'k' // arg
 	Moderated     ChannelMode = 'm'
diff --git a/irc/net.go b/irc/net.go
index 54122f34..e835ab6d 100644
--- a/irc/net.go
+++ b/irc/net.go
@@ -32,10 +32,6 @@ func StringReadChan(conn net.Conn) <-chan string {
 	return ch
 }
 
-const (
-	CRLF = "\r\n"
-)
-
 func maybeLogWriteError(conn net.Conn, err error) bool {
 	if err != nil {
 		if err != io.EOF {
diff --git a/irc/reply.go b/irc/reply.go
index 013ef65b..e018cda6 100644
--- a/irc/reply.go
+++ b/irc/reply.go
@@ -188,7 +188,7 @@ func RplCreated(server *Server) Reply {
 
 func RplMyInfo(server *Server) Reply {
 	return NewNumericReply(server, RPL_MYINFO,
-		"%s %s aiwroOs kn", server.name, VERSION)
+		"%s %s aiOorsw abeIikmntpqrsl", server.name, VERSION)
 }
 
 func RplUModeIs(server *Server, client *Client) Reply {
diff --git a/irc/server.go b/irc/server.go
index 3961b94d..f78a42eb 100644
--- a/irc/server.go
+++ b/irc/server.go
@@ -9,9 +9,6 @@ import (
 	"time"
 )
 
-type ChannelNameMap map[string]*Channel
-type ClientNameMap map[string]*Client
-
 type Server struct {
 	channels ChannelNameMap
 	commands chan<- Command
@@ -125,20 +122,16 @@ func (s *Server) Nick() string {
 	return s.Id()
 }
 
-func (s *Server) DeleteChannel(channel *Channel) {
-	delete(s.channels, channel.name)
-}
-
 //
 // commands
 //
 
 func (m *UnknownCommand) HandleServer(s *Server) {
-	m.Client().Replies() <- ErrUnknownCommand(s, m.command)
+	m.Client().replies <- ErrUnknownCommand(s, m.command)
 }
 
 func (m *PingCommand) HandleServer(s *Server) {
-	m.Client().Replies() <- RplPong(s, m.Client())
+	m.Client().replies <- RplPong(s, m.Client())
 }
 
 func (m *PongCommand) HandleServer(s *Server) {
@@ -147,8 +140,8 @@ func (m *PongCommand) HandleServer(s *Server) {
 
 func (m *PassCommand) HandleServer(s *Server) {
 	if s.password != m.password {
-		m.Client().Replies() <- ErrPasswdMismatch(s)
-		// TODO disconnect
+		m.Client().replies <- ErrPasswdMismatch(s)
+		m.Client().Destroy()
 		return
 	}
 
@@ -170,9 +163,9 @@ func (m *NickCommand) HandleServer(s *Server) {
 		iclient.replies <- reply
 	}
 
-	delete(s.clients, c.nick)
-	s.clients[m.nickname] = c
+	s.clients.Remove(c)
 	c.nick = m.nickname
+	s.clients.Add(c)
 
 	s.tryRegister(c)
 }
@@ -191,9 +184,9 @@ func (m *UserMsgCommand) HandleServer(s *Server) {
 func (m *QuitCommand) HandleServer(s *Server) {
 	c := m.Client()
 
-	delete(s.clients, c.nick)
+	s.clients.Remove(c)
 	for channel := range c.channels {
-		delete(channel.members, c)
+		channel.members.Remove(c)
 	}
 
 	c.replies <- RplError(s, c)
diff --git a/irc/types.go b/irc/types.go
index cdc16f87..01187cac 100644
--- a/irc/types.go
+++ b/irc/types.go
@@ -23,6 +23,73 @@ type ChannelMode rune
 // user-channel mode flags
 type UserChannelMode rune
 
+type ChannelNameMap map[string]*Channel
+
+func (channels ChannelNameMap) Add(channel *Channel) error {
+	if channels[channel.name] != nil {
+		return fmt.Errorf("%s: already set", channel.name)
+	}
+	channels[channel.name] = channel
+	return nil
+}
+
+func (channels ChannelNameMap) Remove(channel *Channel) error {
+	if channel != channels[channel.name] {
+		return fmt.Errorf("%s: mismatch", channel.name)
+	}
+	delete(channels, channel.name)
+	return nil
+}
+
+type ClientNameMap map[string]*Client
+
+func (clients ClientNameMap) Add(client *Client) error {
+	if clients[client.nick] != nil {
+		return fmt.Errorf("%s: already set", client.nick)
+	}
+	clients[client.nick] = client
+	return nil
+}
+
+func (clients ClientNameMap) Remove(client *Client) error {
+	if clients[client.nick] != client {
+		return fmt.Errorf("%s: mismatch", client.nick)
+	}
+	delete(clients, client.nick)
+	return nil
+}
+
+type ClientSet map[*Client]bool
+
+func (clients ClientSet) Add(client *Client) {
+	clients[client] = true
+}
+
+func (clients ClientSet) Remove(client *Client) {
+	delete(clients, client)
+}
+
+func (clients ClientSet) Has(client *Client) bool {
+	return clients[client]
+}
+
+type ChannelSet map[*Channel]bool
+
+func (channels ChannelSet) Add(channel *Channel) {
+	channels[channel] = true
+}
+
+func (channels ChannelSet) Remove(channel *Channel) {
+	delete(channels, channel)
+}
+
+func (channels ChannelSet) First() *Channel {
+	for channel := range channels {
+		return channel
+	}
+	return nil
+}
+
 //
 // interfaces
 //
@@ -36,6 +103,11 @@ type Command interface {
 	HandleServer(*Server)
 }
 
+type ChannelCommand interface {
+	Command
+	HandleChannel(channel *Channel)
+}
+
 //
 // structs
 //